Tumor selective antibodies specific to oncofetal antigen/immature laminin receptor protein

Abstract

Disclosed are high affinity antibodies or antigen-binding fragments thereof, which bind an epitope that lies within the C-terminal region of oncofetal antigen (OFA)/immature laminin receptor protein (iLRP), and which do not substantially cross-react with mature OFA/LRP. The antibodies may be conjugated to cytotoxic moieties to enhance their therapeutic efficacy. Methods of making the antibodies and therapeutic and diagnostic uses thereof are also disclosed.

1 . An antibody or a single-chain or antigen-binding fragment thereof that specifically binds a C-terminal epitope of oncofetal antigen (OFA)/immature laminin protein (iLRP) present on a tumor/cancer cell and which does not substantially cross-react with mature OFA/LRP or with non-cancer cells, wherein the antibody specifically binds an epitope in the C-terminal region of oncofetal antigen (OFA)/immature laminin protein (iLRP) with a binding affinity (K D ) of at least 5.0×10 −1 ° M (±5.0×10 −12  M), as measured by surface plasmon resonance. 
     
     
         2 . The antibody of  claim 1 , wherein the antibody specifically binds an epitope in the C-terminal region of oncofetal antigen (OFA)/immature laminin protein (iLRP) with a binding affinity of at least 4.0×10 −10  M (±5.0×10 −12  M), as measured by surface plasmon resonance. 
     
     
         3 . The antibody of  claim 1 , wherein the antibody specifically binds an epitope in the C-terminal region of oncofetal antigen (OFA)/immature laminin protein (iLRP) with a binding affinity of at least 3.5×10 −10  M (±1.0×10 −11  M), as measured by surface plasmon resonance. 
     
     
         4 . The antibody of  claim 1 , wherein the antibody specifically binds an epitope in the C-terminal region of oncofetal antigen (OFA)/immature laminin protein (iLRP) with a binding affinity of at least 2.0×10 −10  M (±4.0×10 −11  M), as measured by surface plasmon resonance. 
     
     
         5 . The antibody of  claim 1 , wherein the epitope lies within amino acid residues 261-272 (QFPTEDWSAQPA) (SEQ ID NO:5). 
     
     
         6 . The antibody of  claim 1 , wherein the epitope lies within acid residues 261-276 (QFPTEDWSAQPATEDW) (SEQ ID NO:6). 
     
     
         7 . The antibody of  claim 1 , wherein the epitope lies within amino acid residues 217-232 (AAEKAVTKEEFQGEWT) (SEQ ID NO:4). 
     
     
         8 . The antibody of  claim 1 , which is a monoclonal antibody. 
     
     
         9 . The antibody of  claim 8 , which is a murine monoclonal antibody. 
     
     
         10 . The antibody of  claim 1 , which comprises three heavy chain complementarity determining regions (CDRs) which have the sequences GYTFTSYNMH (SEQ ID NO:7), YIYPGNGGTNYNQKFKG (SEQ ID NO:8), and GGYYYGSSWELYFDY (SEQ ID NO:9), and three light chain CDRs which have the sequences RSSQSIVHSNGNTYLE (SEQ ID NO:10), KVSNRFS (SEQ ID NO:11), and FQGSHVPPT (SEQ ID NO:12). 
     
     
         11 . The antibody of  claim 1 , which comprises three heavy chain CDRs which have the sequences GFSLTAYGVN (SEQ ID NO:13), MIWGNGDTDYNSALKS (SEQ ID NO:14), and YGY (SEQ ID NO:15), and three light chain CDRs which have the sequences KSSQSLLDSDGKTYLN (SEQ ID NO:16), LVSKVDS (SEQ ID NO:17), and WQGTHFPFT (SEQ ID NO:18). 
     
     
         12 . The antibody of  claim 1 , which comprises three heavy chain CDRs which have the sequences GFTFSSYTMS (SEQ ID NO:19), TISSGGTYTYYPDSVKG (SEQ ID NO:20), and LRY (SEQ ID NO:21), and three light chain CDRs which have the sequences KSGQSLLDSDGKTYLN (SEQ ID NO:22), LVSKLDS (SEQ ID NO:23), and WQGTHFPQT (SEQ ID NO:24). 
     
     
         13 . The antibody of  claim 1 , comprising three heavy chain CDRs which have the sequences GFSLTSYDIS (SEQ ID NO:25), VIWTGGGTNYNSAFMS (SEQ ID NO:26), and SFVY (SEQ ID NO:27), and three light chain CDRs which have the sequences RSSQSLVHSNGNTYLH (SEQ ID NO:28), KVSNRFS (SEQ ID NO:11), and SQSTHVPWT (SEQ ID NO:29). 
     
     
         14 . The antibody of  claim 1 , which is conjugated to a cytotoxic agent. 
     
     
         15 . A pharmaceutical composition comprising the antibody of  claim 1  or  claim 14 , and a pharmaceutically acceptable carrier. 
     
     
         16 . A method of cancer treatment, comprising administering to a subject with cancer a therapeutically effective amount of the antibody of  claim 1 , which is optionally conjugated to a cytotoxic agent. 
     
     
         17 . The method of  claim 16 , wherein the subject is a human. 
     
     
         18 . The method of  claim 16 , wherein the cancer is a hematopoietic cancer. 
     
     
         19 . The method of  claim 18 , wherein the hematopoietic cancer is leukemia. 
     
     
         20 . The method of  claim 18 , wherein the hematopoietic cancer is lymphoma. 
     
     
         21 . The method of  claim 16 , wherein the cancer is characterized by the presence of a solid tumor. 
     
     
         22 . The method of  claim 21 , wherein the cancer is liver cancer, lung cancer, breast cancer, colon cancer, prostate cancer or pancreatic cancer. 
     
     
         23 . A method of diagnosing cancer in a subject, comprising contacting a tissue or fluid sample obtained from a subject with an antibody of  claim 1 , and detecting complexation of the antibody and OFA/iLRP, wherein relative amount of OFA/iLRP in the sample relative to a control is indicative of a diagnosis of cancer in the subject. 
     
     
         24 . The method of  claim 23 , wherein the antibody is a capture antibody and the detecting comprises an ELISA and wherein a fluid sample obtained from the subject is contacted with the capture antibody disposed on a solid support, so as to allow formation of a complex between the OFA/iLRP and the capture antibody, followed by contacting with a non-cross inhibiting, detectably labeled detection antibody that binds OFA/iLRP and which is different from the capture antibody, detecting complexation of the detection antibody with the OFA/iLRP, and determining relative amount of the OFA/iLRP in the fluid sample relative to a control, wherein elevated amounts of OFA/iLRP in the fluid sample relative to the control is indicative of a diagnosis of cancer. 
     
     
         25 . The method of  claim 24 , wherein the fluid sample is obtained from a human. 
     
     
         26 . The method of  claim 24 , wherein the fluid sample is obtained from a non-human animal. 
     
     
         27 . The method of  claim 24 , wherein the fluid sample is blood or serum. 
     
     
         28 . The method of  claim 24 , wherein the non-human animal is a dog. 
     
     
         29 . The method of  claim 23 , wherein the antibody is detectably labeled. 
     
     
         30 . The method of  claim 29 , wherein the label is a chromogenic agent, a fluorescent agent or a chemiluminescent agent.